Method of reproducing from storage medium storing interactive graphics stream activated in response to user&#39;s command

ABSTRACT

A reproducing method of reproducing from a storage medium video data and graphics data for displaying a menu screen is provided. The reproducing method includes decoding graphics data, outputting the decoded graphics data when an activation command is generated by a user and the decoded graphics data is first graphics data, and outputting the decoded graphics data at a designated time when the decoded graphics data is second graphics data. The outputting of the first graphics data ends when an output finish time is reached and the first graphics data is deleted from a buffer of a decoder that performed the decoding of the graphics data. When the outputting of the first graphics data ends, an activation command generated by the user is ignored.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 11/442,536, filed on May 30, 2006, currentlypending, which is a continuation of application Ser. No. 10/954,357,filed on Oct. 1, 2004, currently pending, which claims the priority ofKorean Patent Application Nos. 10-2004-0002716 and 10-2004-0022042,respectively filed on Jan. 14, 2004 and Mar. 31, 2004, in the KoreanIntellectual Property Office, the disclosures of which are incorporatedherein by reference.

BACKGROUND

1. Field

The following description relates to reproduction of a multimedia image,and more particularly, to method of reproducing from a storage mediumstoring an interactive graphics stream displayed in response to a user'scommand.

2. Description of Related Art

To reproduce a multimedia image, audio-visual (AV) data of themultimedia image, navigation data controlling reproduction of the AVdata, and system data including command information related to a titleof AV data to be initially reproduced when the storage medium isinserted in a reproducing apparatus are recorded in a storage medium.Other data can also be recorded in the storage medium. In particular,the AV data is recorded in the storage medium by multiplexing video,audio, subtitles, and a menu as a main stream.

FIG. 1 illustrates a block diagram of an example of general AV datarecorded in a storage medium.

Referring to FIG. 1, in a storage medium storing a multimedia image, avideo stream 102, an audio stream 104, a presentation graphic stream 106for providing a subtitle, and an interactive graphics stream 108 forproviding a menu screen are multiplexed (MUX) and recorded as a mainstream. Hereinafter, the multiplexed main stream is called AV data 110.

FIG. 2 illustrates a block diagram of an example of a generalreproducing apparatus for reproducing AV data from a storage medium 200in which the AV data 110 is recorded.

Referring to FIG. 2, a reproducing apparatus for reproducing amultimedia image reads navigation data, as described above, and obtainscontrol information required for reproducing the AV data 110. Forexample, the control information includes a coding type of the AV data110, a bit rate, information indicating an area in which the AV data 110is recorded, and the type of data included in the AV data 110. Byreferring to the control information, a reading unit 210, ademultiplexer 220, video, presentation, interactive graphics, and audiodecoders 230, 240, 250, and 260, respectively, are controlled.

In detail, with concurrent reference to FIGS. 1 and 2, the reading unit210 reads multiplexed AV data 110 from a storage medium 200 using theinformation indicating the area in which the AV data 110 is recorded andtransmits the multiplexed AV data 110 to the demultiplexer 220. Thedemultiplexer 220 divides the received AV data 110 into the video stream102, the audio stream 104, the presentation graphic stream 106, and theinteractive graphics stream 108 and transmits the divided streams 102through 108 to the decoders 230 through 260, respectively. Each streamtransmitted to the respective decoder is decoded according to acorresponding data type and ready to be displayed on a screen at adesignated time. The decoded video stream 102, the presentation graphicstream 106, and/or the interactive graphics stream 108 are overlaid as asingle image using a blender 270. Finally, an image selected based on anoutput status set by a user is displayed on the screen. For example, anoutput status can be controlled based on a user's selection such as of asubtitle on/off status and a mute status, etc.

In particular, the interactive graphics decoder 250 receives theinteractive graphics stream 108 from the storage medium 200, decodes theinteractive graphics stream 108, and outputs a menu screen includingbuttons on the screen at a designated time. A user's selection can beinput by the user selecting a specific button on the output menu screen.That is, a user interactive function can be provided.

However, a conventional reproducing apparatus unconditionally outputs amenu screen at a designated time even if a user does not want to watchthe menu when reproducing multimedia such as a movie. If an undesiredmenu screen is displayed when viewing a movie, a user may beinconvenienced.

SUMMARY

In one general aspect, there is provided a reproducing method ofreproducing from a storage medium video data and graphics data fordisplaying a menu screen, including decoding graphics data, outputtingthe decoded graphics data when an activation command is generated by auser and the decoded graphics data is first graphics data, andoutputting the decoded graphics data at a designated time when thedecoded graphics data is second graphics data. The outputting of thefirst graphics data ends when an output finish time is reached and thefirst graphics data is deleted from a buffer of a decoder that performedthe decoding of the graphics data. When the outputting of the firstgraphics data ends, an activation command generated by the user isignored.

The reproducing method may further provide that the first graphics dataand the second graphics data have an identical or similar structurewhich includes a field for individually identifying and discriminatingbetween the first graphics data and the second graphics data.

The reproducing method may further provide that the first graphics dataand the second graphics data have a graphics_segment structure whichincludes a segment_type field defining the type of the first graphicsdata and the type of the second graphics data, respectively.

The reproducing method may further provide that the first graphics dataand the second graphics data have an interactive_composition_segmentstructure which includes a type field for individually identifying anddiscriminating between the first graphics data and the second graphicsdata.

The reproducing method may further provide that the type field isdefined so that, when a value of the type field is 0, the secondgraphics data is indicated, and when a value of the type field is 1, thefirst graphics data is indicated.

The reproducing method may further include blending the second graphicsdata with video data, and displaying the blended data at the designatedtime.

Other features and aspects may be apparent from the following detaileddescription, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a view of an example of conventional AV data recordedin a storage medium.

FIG. 2 illustrates a view of an example of a conventional reproducingapparatus for reproducing a storage medium in which AV data is recorded.

FIG. 3 illustrates an example of a configuration of an interactivegraphics stream.

FIG. 4 illustrates an example of an operation when a normal interactivegraphics stream is reproduced.

FIGS. 5A and 5B illustrate an example of operations when an on-demandinteractive graphics stream is reproduced.

FIGS. 6 a through 6 c illustrate an example of a method ofdiscriminating an on-demand interactive graphics stream from a normalinteractive graphics stream.

FIG. 7 illustrates another example of a method of discriminating anon-demand interactive graphics stream from a normal interactive graphicsstream.

FIG. 8 illustrates another example of a method of discriminating anon-demand interactive graphics stream from a normal interactive graphicsstream.

FIG. 9 illustrates a block diagram of an example of a reproducingapparatus for reproducing an on-demand interactive graphics stream.

FIG. 10 illustrates a block diagram of another example of a reproducingapparatus for reproducing an on-demand interactive graphics stream.

FIGS. 11A-11D illustrate examples of interactive graphics streamsincluded in AV data.

FIG. 12 illustrates an example of a configuration of a player statusregister recording information regarding an interactive graphics stream.

FIG. 13 illustrates another example of a configuration of a playerstatus register recording information regarding an interactive graphicsstream.

FIG. 14 illustrates an example of a process of handling a command foractivating an on-demand interactive graphics stream generated by a user.

FIGS. 15A and 15B illustrate examples of display statuses according tovalues of a disp_flag flag for the configurations of player statusregisters shown in FIGS. 12 and 13, respectively.

FIG. 16 illustrates an example of a system menu of a reproducingapparatus in which menu items for turning an output of an on-demandinteractive graphics stream on/off are defined.

FIG. 17 illustrates a schematic diagram of an example of a remotecontrol including a button for turning an output of an on-demandinteractive graphics stream on/off.

FIG. 18 illustrates a flowchart of an example of a method of reproducinga storage medium on which an interactive graphics stream is recorded.

FIG. 19 illustrates a detailed flowchart of an example of the method ofreproducing a storage medium on which an on-demand interactive graphicsstream illustrated in FIG. 18 is recorded.

Throughout the drawings and the detailed description, unless otherwisedescribed, the same drawing reference numerals will be understood torefer to the same elements, features, and structures. The relative sizeand depiction of these elements may be exaggerated for clarity,illustration, and convenience.

DETAILED DESCRIPTION

The following detailed description is provided to assist the reader ingaining a comprehensive understanding of the methods, apparatuses,and/or systems described herein. Accordingly, various changes,modifications, and equivalents of the systems, apparatuses, and/ormethods described herein will be suggested to those of ordinary skill inthe art. Also, descriptions of well-known functions and constructionsmay be omitted for increased clarity and conciseness.

As used in the present Specification, a normal interactive graphicsstream refers to a data stream which provides a menu screen at adesignated time. Also, as used in the present Specification, anon-demand interactive graphics stream refers to a data stream whichprovides a menus screen which is displayed only when a user desires.

FIG. 3 illustrates an example of a configuration of an interactivegraphics stream.

Referring to FIG. 3, an interactive graphics stream is divided intounits of epochs according to how a decoder operates. Information forreproducing a button on a menu screen including a plurality of buttonsis called an interactive graphics object. All interactive graphicsobjects included in an epoch are decoded and stored in an object bufferof an interactive graphics decoder, to be described later, and unlessdata of a subsequent epoch is input, the stored objects are maintained.Accordingly, in one epoch, the interactive graphics object does not haveto be decoded every time it is used, and the already decoded and storedinteractive graphics objects can be reused. However, when a subsequentepoch starts after one epoch is finished, all buffers of the decoder arereset, and all stored data disappears. Also, the amount of time afterwhich a buffer of the decoder is reset is defined as a specified time.

Display sets are defined as output units of the interactive graphicsobjects, as shown in FIG. 3. A display set indicates a set ofinteractive graphics objects displayed on a single screen, and one epochcan include at least one display set. There are three types of displaysets. The first is an epoch start (ES) display set indicating the startof an epoch, and includes all data for outputting an interactivegraphics such as interactive graphics configuration information requiredfor configuring the interactive graphics and object data used for abutton image. The second is an acquisition point (AP) display set thatcan exist after the ES display set and includes all information forconfiguring an interactive graphic to prepare for a situation such as auser's random search. The third is a normal state (NC) display setincluding data that must be changed among interactive graphics in aprevious display set, i.e., only data to be updated. As shown in FIG. 3,one epoch can include a plurality of display sets. The ES display setexists at an initial part of an epoch, and AP and NC display sets arelocated at subsequent positions. An ES display set is necessary for eachepoch, but the AP and NC display sets are optional.

Each display set includes a composition segment storing configurationinformation of an interactive graphics stream, a plurality of definitionsegments, each recording object data such as a real image of a buttondisplayed on a screen, and an end segment indicating the end of thedisplay set. The composition segment includes output finish timeinformation, button configuration information, and operation informationindicating how a reproducing apparatus responds to a user operation. Thecomposition segment can be realized with an interactive compositionsegment (ICS) data structure. The definition segment includes an objectdefinition segment (ODS) including object data having image informationof a button and a palette definition segment (PDS) including colorinformation adapted to the ODS.

Each segment in a single display set is recorded in a packetizedelementary stream (PES), which is a packet unit of an MPEG-2 transportstream (TS). A relevant display set is decoded at a decoding timeindicated by a decoding time stamp (DTS) included in the PES, and isdisplayed on a screen at a presentation time indicated by a presentationtime stamp (PTS). Also, an output finish time when the output of therelevant display set is complete is determined by acomposition_time_out_pts field value recorded in the ICS indicating adata structure of the composition segment.

Accordingly, the interactive graphics stream is displayed on the screenat a designated time indicated by the PTS, a user command is received,an operation is performed in response there to, and the interactivegraphics stream disappears from the screen at a designated output finishtime indicated by composition_time_out_pts. However, if the interactivegraphics stream is output using only a designated time, a menu screen isunconditionally output at the designated time even if the user does notwant it to. That is, the menu screen can be activated at a time otherthan when the user wants it to, not just when a user wants it to.

Therefore, according to an example, an on-demand interactive graphicsstream activated by a user's command is defined by expanding a functionof the interactive graphics stream to perform a user interactiveoperation. To discriminate from the on-demand interactive graphicsstream defined herein, the interactive graphics stream output at adesignated time is called a normal interactive graphics stream.

The normal interactive graphics stream is displayed on a screen at adesignated time and disappears at a later designated time. On the otherhand, the on-demand interactive graphics stream is displayed on a screenonly when an activation command is generated by a user after all data isdecoded and ready to be output, and performs a designated operation inresponse to an input from the user. That is, as in the normalinteractive graphics stream, in the on-demand interactive graphicsstream, interactive graphics objects such as buttons can first bedisplayed at a time designated by the PTS. However, in the on-demandinteractive graphics stream, the buttons are not displayed on thescreen, unless the user inputs a command to do so.

In the normal interactive graphics stream, the composition_time_out_ptsindicates a time when the buttons are no longer displayed on the screen.However, in the on-demand interactive graphics stream, thecomposition_time_out_pts indicates a time when data related to thebuttons is deleted from the buffer of the decoder. That is, even if abutton activation command is generated by the user after the outputfinish time, since the on-demand interactive graphics stream to beactivated does not exist any longer, the activation command from theuser is ignored.

FIGS. 4, 5A and 5B illustrate an example of an operational differencebetween a normal interactive graphics stream (FIG. 4) and an on-demandinteractive graphics stream (FIGS. 5A and 5B).

FIG. 4 illustrates an operation when a normal interactive graphicsstream is reproduced. Referring to FIG. 4, normal interactive graphicsstreams are multiplexed in AV data. Each decoded normal interactivegraphics stream is displayed on a screen according to a PTS included inan ICS of an ES display set. Here, a user can navigate or select buttonsdisplayed on the screen. According to a user command, an operationassigned a button is performed.

For example, when navigating a button, a state of the button is changedfrom a selected state to an unselected state, an output image of thebutton is changed so as to be suitable for the unselected state, andwhen the user selects a specific button, an operation according to anavigation command assigned to the specific button is performed. Also,when the command assigned to the specific button is a command to move toanother location of the AV data, even if an output finish time(composition_time_out_pts) of the normal interactive graphics stream hasnot been reached yet, the specific button disappears from the screen,and AV data indicated by the move command is displayed on the screen. Onthe other hand, when the command assigned to the specific button is notthe command to move to another location of the AV data, the commanddefined to the specific button is performed, an output state of eachbutton is maintained until the output finish time(composition_time_out_pts) is reached, and when the output finish time(composition_time_out_pts) is reached, the specific button disappearsfrom the screen. That is, a normal interactive graphics stream isdisplayed on a screen at a designated time, and when a designated outputfinish time is reached, the normal interactive graphics streamdisappears from the screen.

FIGS. 5A and 5B illustrate an example of operations when an on-demandinteractive graphics stream is reproduced.

Referring to FIG. 5A, on-demand interactive graphics streams aremultiplexed in AV data. When an on-demand interactive graphics stream isdecoded, the on-demand interactive graphics stream is ready to beactivated. Even if the on-demand interactive graphics stream is ready tobe activated, a relevant button is displayed on a screen only if auser's command is generated, in which case, a user command can bereceived. The relevant button displayed on the screen disappears fromthe screen when an output finish time (composition_time_out_pts) isreached. Also, all decoded data in a buffer of a decoder disappears whenthe output finish time is reached by setting an epoch to the outputfinish time. Therefore, a user's activation command received after theoutput finish time is ignored.

Referring to FIG. 5B, as with the normal interactive graphics streamshown in FIG. 4, an epoch can be defined to terminate before it reachesa subsequent ICS of an ES display set. In this case, since all relevantdata in a buffer of a decoder is deleted when the subsequent ICS of theES display set is reached, even if an output finish time(composition_time_out_pts) has been reached, the relevant data does nothave to be deleted from the decoder. However, even if an activationcommand of a menu is generated by a user after the output finish time isreached, a selected button is not reproduced by recognizing that a validinteractive display duration has ended. That is, a user's activationcommand received after the output finish time is ignored.

As described above, an on-demand interactive graphics stream and anormal interactive graphics stream have a similar data structure.However, a difference between the two streams is that the displaying ofa button on a screen is determined by a user's activation command in theon-demand interactive graphics stream and by a designated time in thenormal interactive graphics stream. That is, if only information fordiscriminating two types of interactive graphics streams is added, thesame data structure can be used for realizing the two types ofinteractive graphics streams.

Additional methods of discriminating the on-demand interactive graphicsstream from the normal interactive graphics stream are as follows:

First method: a method of discriminating the two streams by using asegment_type field of an ICS

Second method: a method of discriminating the two streams by adding anICS_type field to the ICS

Third method: a method of discriminating the two streams by defining anOn_demand_ICS structure as a new structure of the on-demand interactivegraphics stream.

FIGS. 6A through 6C illustrate an example of a method (the first method)of discriminating an on-demand interactive graphics stream from a normalinteractive graphics stream.

Referring to FIGS. 6A and 6B, a graphics_segment structure includes asegment_descriptor 602 which includes a segment_type field 604indicating a segment type. In FIG. 6C, segment types, which thesegment_type field 604 can indicate, are defined. In the first method,the segment_type field 604 can be defined such that a normal interactivegraphics stream type (Normal_ICS) 606 has a value 0x18 and an on-demandinteractive graphics stream type (On_demand_ICS) 607 has a value 0x19.That is, the first method discriminates the two types of interactivegraphics streams using the segment_type field 604 when the two types ofinteractive graphics streams have the same structure.

FIG. 7 illustrates another example of a method (the second method) ofdiscriminating an on-demand interactive graphics stream from a normalinteractive graphics stream.

Referring to FIG. 7, on-demand and normal interactive graphics streamshave the same structure (interactive_composition_segment), and in thesecond method, the two types of interactive graphics streams arediscriminated using an ICS_type field 702. That is, the ICS_type fieldis defined so that, if a value of ICS_type is 0, ICS_type indicates anormal interactive graphics stream, and if a value of ICS_type is 1,ICS_type indicates an on-demand interactive graphics stream.

FIG. 8 illustrates another example of a method (the third method) ofdiscriminating an on-demand interactive graphics stream from a normalinteractive graphics stream.

Referring to FIG. 8, a newly defined an On_demand_ICS structure isshown. Unlike the first and second methods in which the same structureis used, in the third method, a new structure of an on-demandinteractive graphics stream is defined.

Unlike a structure of a normal interactive graphics stream, theOn_demand_ICS structure, the new structure of the on-demand interactivegraphics stream defines pages to be configured operation by operationsuch as an initial menu page including an initial button informing auser that the on-demand interactive graphics stream is decoded and isready to be activated by the user and pages including buttons to bedisplayed after the on-demand interactive graphics stream is activatedby the user, i.e., a first menu page through an nth menu page. Each menupage to be displayed can include reproduction information of at leastone button to be displayed and command information indicating whatoperation will be performed if the button is selected.

On the basis of an example of an on-demand interactive graphics streamdescribed herein, an example of a configuration of a reproducingapparatus supporting the on-demand interactive graphics stream will bedescribed.

FIGS. 9 and 10 illustrate block diagrams of examples of reproducingapparatuses for reproducing an on-demand interactive graphics stream.

Referring to FIG. 9, an example of an interactive graphics decoder 910of a reproducing apparatus is shown. AV data read from a storage mediumis input to a packet identifier (PID) filter 902, and only aninteractive graphics stream is selectively transmitted to a transportbuffer 904 and decoded by the interactive graphics decoder 910.

In the interactive graphics decoder 910, the interactive graphics streamis temporarily stored in a coding data buffer 912 and then transmittedto a stream graphics processor 914. After the interactive graphicsstream is decoded by the stream graphics processor 914, button imageobject data is transmitted to an object buffer 916, and buttonconfiguration information is transmitted to a composition buffer 918. Agraphics controller 920 builds output images for received object datawith reference to relevant configuration information and transmits thebuilt image to a graphics plane 930. That is, at the time identified bya PTS, an output start time of an interactive graphics stream, thegraphics controller 920 determines an image to be displayed on a screenand transmits the determined image from the object buffer 916 to thegraphics plane 930. The transmitted image is output with reference to acolor lookup table (CLUT) 932 according to color information included inthe relevant configuration information. Also, the graphics controller920 may change a button state according to a move or selection of abutton in response to a user command and adapt this result to a screenoutput.

Particularly, FIG. 9 shows a block diagram of a reproducing apparatusconfigured such that a normal interactive graphics stream and anon-demand interactive graphics stream use the same buffer memory. Sincethe two types of interactive graphics streams use the same buffer of thedecoder 910 as shown in FIG. 9, only one of the normal interactivegraphics stream and the on-demand interactive graphics stream can existin the buffer of the decoder 910 at a given time. That is, only one typeof interactive graphics stream can be processed at once.

FIG. 10 illustrates a block diagram of another example of a reproducingapparatus for reproducing an on-demand interactive graphics stream.

Referring to FIG. 10, a reproducing apparatus configured such that anormal interactive graphics stream and an on-demand interactive graphicsstream are stored in separate buffer memories is shown. That is, thenormal interactive graphics stream is stored in a normal ICS memory area1010, and the on-demand interactive graphics stream is stored in anon-demand ICS memory area 1020. Therefore, the two types of interactivegraphics streams can simultaneously exist in buffers. In this case, whena normal interactive graphics stream is input in a state where anon-demand interactive graphics stream exists in a buffer, or when anon-demand interactive graphics stream is input in a state where a normalinteractive graphics stream exists in a buffer, the buffer memory of adecoder does not have to be reset. However, when the two types ofinteractive graphics streams are simultaneously displayed on a screen,it may not be clear which object a user operation is related to, andadapting color information to a screen configuration can be problematic.Therefore, even though not shown in FIG. 10, the reproducing apparatuscan further include a control unit selecting the normal interactivegraphics stream or the on-demand interactive graphics stream to beoutput and the respective CULT block for the interactive graphicsstream.

FIG. 11 illustrates an example of an interactive graphics streamincluded in AV data.

Referring to FIG. 11, FIG. 11A shows a case where only on-demandinteractive graphics streams are recorded in single AV data. FIG. 11Bshows a case where only normal interactive graphics streams are recordedin single AV data. FIG. 11C shows a case where two types of interactivegraphics streams are mixed and recorded in single AV data. FIG. 11Dshows a case where two types of interactive graphics streams are mixedand recorded in single AV data and on-demand interactive graphicsstreams are separated from the other AV data and recorded. Inparticular, referring to FIG. 11D, when the AV data is read from thebeginning, on-demand ICS data recorded at the beginning of the AV datais referred to. However, when the AV data is read from a middleposition, since only configuration information is recorded in the AVdata while object data of a real button image is separately recorded,the button is output using the separately recorded object data withreference to the configuration information recorded in the AV data. Inthis case, unnecessary data redundancy can be prevented by separatelyrecording the object data.

On the basis of the data configurations of an on-demand interactivegraphics stream and the configurations of a reproducing apparatusdescribed above, an example of a process of outputting the on-demandinteractive graphics stream to a screen according to a user's activationcommand will be described.

FIGS. 12 and 13 illustrate examples of configurations of player statusregisters for recording information regarding an interactive graphicsstream.

Referring to FIG. 12, in a player status register (PSR), a number of aninteractive graphics stream being currently reproduced or an interactivegraphics stream to be reproduced later is recorded. In FIG. 12, thenumber is recorded in bit0-bit7 of a PSR 0. Therefore, even whenreproduction of a multimedia image is temporarily stopped and restarted,an interactive graphics stream that was being reproduced just before canbe reproduced again by referring to the PSR 0.

In a reproducing apparatus supporting both normal interactive graphicsstream and on-demand interactive graphics stream, it must be determinedwhether a stream number recorded in the PSR 0 is a number indicating thenormal interactive graphics stream or the on-demand interactive graphicsstream. Therefore, an example of a reproducing apparatus includes anICS_usage flag for determining whether an interactive graphics streamnumber recorded in the PSR 0 is a number indicating the normalinteractive graphics stream or the on-demand interactive graphicsstream. In FIG. 12, the ICS_usage flag is recorded in bit30 of the PSR0. That is, if a stream being currently reproduced is an on-demandinteractive graphics stream, the ICS_usage flag is set to 1, and if thestream being currently reproduced is a normal interactive graphicsstream, the ICS_usage flag is set to 0.

Also, in an on-demand interactive graphics stream, a disp_flag flag isdefined to indicate whether the stream is to be displayed on a screen.In FIG. 12, the disp_flag flag is recorded in bit31 of the PSR 0. If thedisp_flag flag is set to 1, when an on-demand interactive graphicsstream is ready to be activated, the reproducing apparatus displays aninitial menu page on the screen to inform a user that the on-demandinteractive graphics stream is ready to be activated. If the disp_flagflag is set to 0, the reproducing apparatus does not display aninteractive graphics on the screen.

On the other hand, when the disp_flag flag is set to 0 and an on-demandinteractive graphics stream is ready to be activated, that is, when theon-demand interactive graphics stream is ready to be activated and theon-demand interactive graphics stream is not to be displayed on thescreen, there are two methods of processing the on-demand interactivegraphics stream. In the first method, the reproducing apparatus isconfigured such that the on-demand interactive graphics stream isactivated when an activation command is generated by a user. In thesecond method, the reproducing apparatus is configured such that theon-demand interactive graphics stream is not activated and the user'scommand is ignored when generated by the user.

FIG. 13 illustrates another example of a configuration of a playerstatus register recording information regarding an interactive graphicsstream. Referring to FIG. 13, a reproducing apparatus configured torecord two types of interactive graphics streams in separate PSRs isshown. That is, a case where information regarding a normal interactivegraphics stream is recorded in a PSR 0 and information regarding anon-demand interactive graphics stream is recorded in a PSR 11 is shown.

If an ICS_type field indicates a normal interactive graphics stream,information regarding the normal interactive graphics stream is recordedin the PSR 0, and if the ICS_type field indicates an on-demandinteractive graphics stream, information regarding the on-demandinteractive graphics stream is separately recorded in the PSR 11.Accordingly, unlike the configuration shown in FIG. 12, an ICS_usageflag for determining an ICS type of an interactive graphics stream isnot required. However, in the PSR 11, it is required that a disp_flagflag indicating whether an initial menu page for informing a user thatan on-demand interactive graphics stream is ready to be activated isdisplayed on a screen, and the operation of the disp_flag flag is thesame as FIG. 12. In FIG. 13, the disp_flag flag is recorded in bit31 ofthe PSR 11.

FIG. 14 illustrates an example of a process of handling a command foractivating an on-demand interactive graphics stream generated by a user.

Referring to FIG. 14, when an activation command is generated by a user,a reproducing apparatus determines whether an on-demand interactivegraphics stream is ready to be activated in an interactive graphicsdecoder, and if the on-demand interactive graphics stream is ready to beactivated, the on-demand interactive graphics stream is displayed on ascreen, a focus is set to receive a user command, and a button selectionfrom the user is ready to be received. If the on-demand interactivegraphics stream is not ready to be activated, an activation command fromthe user is ignored, or a message informing the user that an on-demandinteractive graphics stream to be output does not exist is displayed onthe screen.

FIGS. 15A and 15B illustrate examples of display statuses according tovalues of a disp_flag flag for the configurations of player statusregisters shown in FIGS. 12 and 13, respectively.

Referring to FIG. 15A, when a disp_flag flag is set to 1, if anon-demand interactive graphics stream is decoded and ready to beactivated, an initial menu page is displayed on a screen informing auser that the on-demand interactive graphics stream is ready to beactivated. If an activation command for the on-demand interactivegraphics stream is generated by the user, a first menu page is displayedon the screen.

Referring to FIG. 15B, when the disp_flag flag is set to 0, the initialmenu page is not displayed on the screen even if the on-demandinteractive graphics stream is decoded and ready to be activated.However, when an activation command for the on-demand interactivegraphics stream is generated by the user, a reproducing apparatus can beconfigured so that the activation command is ignored or the first menupage is displayed on the screen.

FIG. 16 illustrates an example of a system menu of a reproducingapparatus in which menu items for turning an output of an on-demandinteractive graphics stream on/off are defined. If a user sets anOn-demand ICS Display item on, a disp_flag flag of a status registerstoring information regarding the on-demand interactive graphics stream,for example, the PSR 0 or the PSR 11 described above, is set to 1. Onthe other hand, if the user sets the On-demand ICS Display item off, thereproducing apparatus sets the disp_flag flag of the status register as0. That is, the disp_flag flag can be changed using a user interface,which is called the system menu.

FIG. 17 illustrates a schematic diagram of an example of a remotecontrol including a button for turning an output of an on-demandinteractive graphics stream on/off. A user can set a disp_flag flag of astatus register to 0 or 1 by pushing a relevant button.

On the basis of the data configurations of an on-demand interactivegraphics stream and the configurations of a reproducing apparatusdescribed above, an example of a reproducing method will now bedescribed.

FIGS. 18 and 19 illustrate flowcharts of examples of a method ofreproducing a storage medium on which an interactive graphics stream isrecorded.

Referring to FIG. 18, an interactive graphics stream is read from astorage medium storing normal interactive graphics streams, and/oron-demand interactive graphics streams, in operation 1802. The readinteractive graphics stream is checked in operation 1804. The type ofthe decoded interactive graphics stream is checked in operation 1806. Ifthe decoded interactive graphics stream is a normal interactive graphicsstream, the decoded interactive graphics stream is blended with videodata and displayed on a screen at a designated time in operation 1808.If the decoded interactive graphics stream is an on-demand interactivegraphics stream, the decoded interactive graphics stream is blended withthe video data and displayed on the screen only if an activation commandis generated by a user in operation 1810.

FIG. 19 illustrates a detailed flowchart of an example of the process ofreproducing the on-demand interactive graphics stream illustrated inFIG. 18.

Referring to FIG. 19, if the decoded interactive graphics stream is anon-demand interactive graphics stream, a disp_flag flag indicatingwhether the on-demand interactive graphics stream is to be displayed onthe screen is read from a player status register in operation 1902. If avalue of the disp_flag flag is 1 in operation 1904, an initial menu pageinforming the user that the on-demand interactive graphics stream isready to be activated is displayed on the screen in operation 1906. Ifthe user inputs an activation command when the output initial menu pageis displayed in operation 1908, a menu page demanding on the usercommand is displayed on the screen in operation 1910.

On the other hand, if the value of the disp_flag flag is 0 in operation1904, nothing is displayed on the screen, and even if an activationcommand is generated by the user in operation 1920, the activationcommand is ignored in operation 1922. Even though it is not shown inFIG. 19, if the value of the disp_flag flag is 0, nothing is displayedon the screen, and if an activation command is generated by the userusing a user interface such as a remote control, the initial menu pageis displayed on the screen.

By using an on-demand interactive graphics stream according to theexamples described above, the on-demand interactive graphics stream canbe controlled so that it is displayed on and disappears from a screen atdesignated times or displayed on the screen only if a user generates acommand.

According to the examples described above, an interactive graphics suchas a button can be controlled by using an on-demand interactive graphicsstream so that the button is displayed on a screen when a user generatesa command.

Also, an interactive graphics stream specialized for a relevant area canbe configured by configuring different on-demand interactive graphicsstreams for certain areas or chapters of AV data. For example, insteadof buttons performing fixed functions, information related toactors/actresses, properties, and shooting locations existing in certainareas included in multimedia images can be provided to a user.

Furthermore, the number of buttons on a remote control can be reduced byconfiguring functions corresponding to the buttons of the remote controlwith a menu driven method using an on-demand interactive graphicsstream.

A number of examples have been described above. Nevertheless, it will beunderstood that various modifications may be made. For example, suitableresults may be achieved if the described techniques are performed in adifferent order and/or if the components in a described system,architecture, device, or circuit are combined in a different mannerand/or replaced or supplemented by other components or theirequivalents. Accordingly, other implementations are with the scope ofthe following claims.

What is claimed is:
 1. A reproducing method of reproducing from astorage medium video data and graphics data for displaying a menuscreen, comprising: decoding graphics data; outputting the decodedgraphics data when an activation command is generated by a user and thedecoded graphics data is first graphics data; and outputting the decodedgraphics data at a designated time when the decoded graphics data issecond graphics data, wherein: when a predetermined time is reached, thefirst graphics data is deleted from a buffer of a decoder that performedthe decoding of the graphics data.
 2. The reproducing method of claim 1,wherein the first graphics data and the second graphics data have anidentical or similar structure which includes a field for individuallyidentifying and discriminating between the first graphics data and thesecond graphics data.
 3. The reproducing method of claim 2, wherein thefirst graphics data and the second graphics data have a graphics_segmentstructure which includes a segment_type field defining the type of thefirst graphics data and the type of the second graphics data,respectively.
 4. The reproducing method of claim 2, wherein the firstgraphics data and the second graphics data have aninteractive_composition_segment structure which includes a type fieldfor individually identifying and discriminating between the firstgraphics data and the second graphics data.
 5. The reproducing method ofclaim 4, wherein the type field is defined so that, when a value of thetype field is 0, the second graphics data is indicated, and when a valueof the type field is 1, the first graphics data is indicated.
 6. Thereproducing method of claim 1, further comprising: blending the secondgraphics data with video data; and displaying the blended data at thedesignated time.